Horsehead Nebula (Barnard 33) | Constellation Guide Constellation Guide Constellations: A Guide to the Night Sky Horsehead Nebula (Barnard 33) by admin The Horsehead Nebula is a famous diffuse dark nebula found in the Orion Molecular Cloud Complex in the constellation Orion . It is a dark cloud composed of dust and gas where star formation is taking place. The nebula is also known as Barnard 33, and is located in the emission nebula IC 434. The Horsehead Nebula is approximately 1,500 light years distant from Earth. The Horsehead Nebula is one of the most easily identifiable nebulae in the sky as its shape resembles that of a horse’s head and neck when observed from Earth. The swirling clouds of gas and dark dust are lit by a pinkish glow of hydrogen gas located behind the nebula and ionized by the nearby bright star Sigma Orionis. Sigma Orionis, which is in fact a five-star system, illuminates the entire region. The brighter star visible in this area of the sky in images is Zeta Orionis, but it is located in the foreground and not related to the Horsehead Nebula.

The nebula formed from a collapse of an interstellar cloud of material and appears dark mainly because of the thick dust in the neighbouring area, with the bright spots at the base marking hidden protostars, newly formed or forming young stars. Horsehead Nebula (Barnard 33), image: NASA The Horsehead can only be seen because its obscuring dust is silhouetted against the brighter nebula IC 434. The nebulous region that forms the horse’s head is just part of a larger dust cloud. The nebula is really an extremely dense cloud projecting in front of the ionized hydrogen gas. This is revealed by the fact that lower side of the horse’s neck is particularly dark and casts a shadow to the east. The glowing hydrogen gas marks the edge of the dark cloud that forms the nebula, which is evident in the notable change in the density of visible stars on either side of the cloud. The brighter region at the top left edge of the Horsehead is a young star still hidden in the gas and dust in which it was formed. The jutting pillar that forms the Horsehead has a high density of helium and hydrogen, which makes it hard to erode.

While the gas clouds that surrounded the nebula have already dissipated, it will be another five million years before the pillar dissipates too. FACTS, LOCATION AND SIZE The Horsehead Nebula is one of the best known and most photographed stellar nurseries in the night sky. It can contain more than a hundred known gases, both organic and inorganic, and also complex, large organic molecules of dust. The nebula was first recorded on a photographic plate in 1888 by the Scottish astronomer Williamina Fleming at the Harvard College Observatory. In April 2013, the Hubble Space Telescope photographed the nebula in astounding detail, revealing two new stars located in the top ridge. NASA explained in a release that one of these stars is emitting “harsh ultraviolet glare” which is slowly stripping away the cloud. “Gas clouds surrounding the Horsehead already have dissipated, but the tip of the jutting pillar contains a slightly higher density of hydrogen and helium, laced with dust,” said NASA.

“This casts a shadow that protects material behind it from being stripped away by intense stellar radiation evaporating the hydrogen cloud, and a pillar structure forms.” The wide-field VISTA view includes the glow of the reflection nebula NGC 2023, just below centre, and the ghostly outline of the Horsehead Nebula (Barnard 33) towards the lower right. Image: ESO/J. Emerson/VISTA The Orion Molecular Cloud Complex, which contains the Horsehead Nebula, is also home to the famous Orion Nebula (Messier 42), the Flame Nebula (NGC 2024), and Barnard’s Loop. As one of the nearest regions where massive stars are formed, the cloud complex is also most easily photographed, making these some of the most recognizable objects in the sky. The Horsehead Nebula can be found just to the south of Alnitak, Zeta Orionis, the easternmost star of Orion’s Belt . It is 2-3 light years across and a challenging object to find with a small telescope. The nebula appears shadowy in optical light, but transparent at infrared wavelengths, revealing the Milky Way and galaxies in the background.

Horsehead Nebula (Barnard 33) Apparent size: 8 x 6 arcminutes Magnitude: 6.8 Designations: Barnard 33, IC 434, LDN 1630, M3T 31, [OS98] 52 IMAGES Region of the Horsehead Nebula south of star Alnitak in Orion, image: Hewholooks at wikipedia.org Astronomers have used NASA’s Hubble Space Telescope to photograph the iconic Horsehead Nebula in a new, infrared light to mark the 23rd anniversary of the famous observatory’s launch aboard the space shuttle Discovery on April 24, 1990. Looking like an apparition rising from whitecaps of interstellar foam, the iconic Horsehead Nebula has graced astronomy books ever since its discovery more than a century ago. The nebula is a favorite target for amateur and professional astronomers. It is shadowy in optical light. It appears transparent and ethereal when seen at infrared wavelengths. The rich tapestry of the Horsehead Nebula pops out against the backdrop of Milky Way stars and distant galaxies that easily are visible in infrared light.

Hubble has been producing ground-breaking science for two decades. During that time, it has benefited from a slew of upgrades from space shuttle missions, including the 2009 addition of a new imaging workhorse, the high-resolution Wide Field Camera 3 that took the new portrait of the Horsehead. Image: NASA/ESA/Hubble Heritage Team This spectacular visible light wide-field view of part of the famous belt of the great celestial hunter Orion shows the region of the sky around the Flame Nebula . The whole image is filled with glowing gas clouds illuminated by hot blue young stars. It was created from photographs in red and blue light forming part of the Digitized Sky Survey 2. The field of view is approximately three degrees. Image: ESO and Digitized Sky Survey 2 A reproduction of a composite colour image of the Horsehead Nebula and its immediate surroundings. It is based on three exposures in the visual part of the spectrum with the FORS2 multi-mode instrument at the 8.2-m KUEYEN telescope at Paranal.

It was produced from three images, obtained on February 1, 2000, with the FORS2 multi-mode instrument at the 8.2-m KUEYEN Unit Telescope and extracted from the VLT Science Archive Facility . The frames were obtained in the B-band (600 sec exposure; wavelength 429 nm; FWHM 88 nm; here rendered as blue), V-band (300 sec; 554 nm; 112 nm; green) and R-band (120 sec; 655 nm; 165 nm; red). The original pixel size is 0.2 arcsec. The photo shows the full field recorded in all three colours, approximately 6.5 x 6.7 arcmin 2 . The seeing was about 0.75 arcsec.

Image: ESO VIDEO Horsehead Nebula: Well-known Object is Hard to Find Horsehead Nebula: Well-known Object is Hard to Find By Nola Taylor Redd, Space.com Contributor | July 10, 2012 06:43pm ET MORE One of the best-known objects in the sky, the Horsehead Nebula strikes a memorable figure, illuminated from behind by a larger cloud of charged gas. Heated by a nearby star, the gas and dust form the familiar shape of an equine head. Friday, March 4, 2011: The Canada-France-Hawaii Telescope produced this stunning image of the well-known Horsehead Nebula. It is part of an enormous cloud of molecular gas and dust obscuring background light from nearby emission nebula IC 434, producing the silhouette. --Tom Chao Credit: Canada-France-Hawaii Telescope/Coelum Sculpted gas Lying 1,500 light-years from the sun, just south of the easternmost star in Orion's Belt, the Horsehead Nebula at first glance appears to be a distinctive hole cut in the vibrant backdrop of another nebula, IC 434.

However, the darkness is actually a cloud of predominantly hydrogen gas that stands out because of the glow from the pinkish background gas. Known as an emission cloud, the intriguing shape of the nebula is sculpted by radiation from the stars around it. The dark gas extends below the more obvious horse's head into a shapeless blob beneath it. [ GALLERY: Strange Nebula Shapes, What Do You See? ] On the eleventh anniversary of the Hubble Space Telescope , internet voters selected the Horsehead Nebula as a target to be imaged by the orbiting observer. Discovery Although most people know the distinctive cloud of gas as the Horsehead Nebula, its official name is Barnard 33, or B33. It was first imaged at Harvard College Observatory in 1888 on photographic plates. Frustrated with his male assistants, astronomy professor Edward Pickering famously claimed that his maid could do a better job of identifying and cataloging the extensive collection of images taken at the observatory. He hired his maid, Williamina Fleming, along with several other women, who became known as "computers." Fleming proved Pickering's point.

In addition to discovering the Horsehead Nebula, Fleming discovered 58 other gaseous nebulae, 10 novae, and more than 300 variable stars. She eventually became the first American woman to be elected an honorary member of the Royal Astronomical Society of London. [ 50 Fabulous Deep-Space Nebula Photos ] In 1894, American astronomer Edward Barnard photographed the distinctive nebula from the Lick Observatory in California, adding it to his list of dark nebula (and resulting in its official moniker). The first use of its fitting common name is lost in history. Searching the sky The Horsehead Nebula is a prime target for many amateur astronomers, despite the difficulty many have viewing it. Upgrades in technology have made observations easier with inexpensive equipment, but it can still be a challenge to pick out of the sky. Glare from a nearby star makes it difficult to spot, as does its small size. Despite the many challenges, the Horsehead Nebula makes for an enjoyable find for the amateur astronomer. — Nola Taylor Redd The Horsehead Nebula Finder Kit The Horsehead Nebula Finder Kit by Jeffrey L.

Polston (January 20, 1999) In the world of astronomy, there are thousands upon thousands of objects in the heavens for us to explore. Some range from very bright naked eye magnitudes, while some lay at the extreme edge of detection with a large aperture telescope. Some are big, covering several degrees of sky, while others are tiny, measured in small arc seconds. Out of these objects, we all have favorites. Some people like open clusters while others prefer the globulars. Some people like galaxies while others go more for the nebula that dot our nightly skies. Even among our favorite objects, we still revere some with a special uniqueness. We all have our personal reasons for chasing our various astronomical quarry. This article was written to help as a guide toward an object that is special to me. It's an object of obvious beauty. It has a very unique characteristic. You can show a picture of it to anyone, whether they be amateur astronomers or not, and they will at least get part of it's name correct. They might not know what they are looking at, but they will definitely tell you what it looks like.

Unlike M17, which some people call the Swan nebula, while others call it the Omega nebula, this object is not open to interpretation. What is this object? I'm talking about the Horsehead nebula. The Horsehead nebula is a dark nebula located in the constellation of Orion. As the name implies, this dark nebula, silhouetted by the glowing emission nebula behind it, looks like a horse's head. It reminds me of a knight chess piece. Of all the objects in the sky, this is one that looks exactly like it is named. It is located about 30 arc minutes south of the bright, 2nd magnitude star Alnitak. Alnitak is the left most belt star of Orion. "That's easy", you say, "I can point my telescope at Alnitak without even looking". Yes that's true. While you can probably easily point your telescope directly at the Horsehead nebula, you'll find it very difficult to actually see the Horsehead nebula. The Horsehead nebula is very faint and takes excellent skies to be seen. Even then, you need a trained eye to be able to pick it out of the black background of space.

Remember, it is a dark nebula. I've been searching for the Horsehead nebula every since I heard of it. When I saw the beautiful picture of that dark nebula nestled in amongst the glowing red of some emission nebula, I just had to see it with my own eyes. At the time I didn't know what dark nebula or emission nebula were. I just wanted to see this awesome object that looks exactly like its namesake. It's right beside of Alnitak. "Easy", I say. I pointed my 60mm refractor at the star. What did I see? Nothing! Well, I did see Alnitak. Month after month I tried. Year after year I would glance towards the heavens at night, trying to spot this elusive object. My observing skills and my instruments advanced. I used my 8" f/4.5 Newtonian. Nothing. I used my 8" f/10 Schmidt-Cassegrain. Nothing. I used my 10" f/4.5 Newtonian. Nothing. As my knowledge of astronomical objects grew, I began to realize why I was failing at seeing the Horsehead nebula, despite my valiant efforts.

I knew I was looking right at it but still not seeing it. I read of success reports from people who purchased a special $100 filter just for finding the Horsehead nebula. With large "light buckets" and these super filters, the sightings seemed quite routine to them. But I didn't want it to be that easy. Besides not having a large telescopic "light bucket" nor the desire to spend $100 hard earned dollars on a one object filter, I was driven to see it with my current arsenal of telescopes. I would allow myself to use a narrow band filter since it's a great observing aid to have in your astronomical toolbox anyway. So, now that we know what the Horsehead is and basically where it is located, how do we go about actually finding it and most importantly, confirming that we can actually see it? Well, that's the purpose of this "kit". With the instructions, directions, hints, and charts of this kit, hopefully the elusive Horsehead nebula will finally be "roped" and observed. Telescope Size I've heard of people spotting the Horsehead nebula with telescopes in the 6" size range.

Seems like I've even heard of people seeing it in smaller instruments. I've also heard of people not seeing it in huge telescopes with mirrors in the 20" range. The usual minimum size that I've seen most people recommend is an 8" telescope. Of course, the larger the telescope the better. Don't be disappointed by negative sightings with bigger instruments. Seeing conditions and experience have a lot to do with viewing the Horsehead nebula. Image orientation Do you know the image orientation of your telescope? It can vary depending on the type of telescope you have and the accessories you use. First there is the normal image, sometimes referred to as a corrected or erect image view. This is the view you get when you use your own eyes to view something. You will also get this type of image if you use an erect image prism on a refractor or Schmidt-Cassegrain telescope. The prisms are sometimes referred to as amici prisms. A second type of view is a common astronomical telescope image. This is what you get when you use a refractor or Schmidt-Cassegrain without any kind of diagonal. The image is inverted, or upside down. This is also the view through a Newtonian reflecting telescope.

The last type of view is the mirror image. This is what you get when you use a diagonal with a refractor or Schmidt-Cassegrain telescope. The image is erect, but is flipped left to right. Finder Charts and Images I have created a few charts and images of the area around the Horsehead nebula. Use the one that matches your telescope configuration. Figure 1 is an actual image of the Horsehead nebula. Figure 2 is a chart of the Horsehead nebula with a normal view. Figure 3 is a chart of the Horsehead nebula with a mirror view. Both charts of Figure 2 and Figure 3 have the guide stars labeled. Figure 4 and Figure 5 are negative images of Figure 1. Figure 4 is a normal image while Figure 5 is a mirror image. Some people like to use actual images at the telescope. Use which ever image or chart that you like the best. Filters As I have mentioned previously, there is a special filter that one could use to see objects such as the Horsehead nebula. It's called a hydrogen-beta filter. They sell for about $100.

Since I don't want to spend that kind of money on a filter that will only be useful on a handful of objects, the filter I use is a Lumicon UHC, which is a narrow band filter. This is a good, general purpose filter and may help you in your search. Starting Point Well, the most obvious starting point is the leftmost belt star of Orion, Alnitak. Alnitak is a 1.7 magnitude blue-white star. At 817 light-years distance, it blazes in the eyepiece. In fact, it's so bright that it can hinder your efforts to see the Horsehead nebula. Sometimes glare from Alnitak will bleed over into your field of view, making it difficult to see the faint nebulosity in the region. Even so, it's a great jumping off point because it is easy to find and it lies so near to the Horsehead nebula. Another reason it is a good staring point is because right next to Alnitak is a nebula that will help you gauge the conditions of the skies and whether or not an attempt to see the Horsehead nebula is even worth your time.

So, to begin your quest, center Alnitak in a low power eyepiece. While you're there, take in the dazzling beauty of this spectacular star. Located 18minutes north east of Alnitak is a truly spectacular nebula. It goes by a few names. I've heard it called the Tank Tracks. I call it the Flame Nebula. To me, with its dark divisions, it looks just like a burning bush. Because of its proximity to bright Alnitak, and its visibility being dependent on the sky conditions, this nebula is easy to overlook. I had been looking at Alnitak for years and never knew the nebula was there. When a fellow observer showed it to me during a telescope purchase, I was amazed that such a beautiful sight had eluded me. Again, seeing the Flame Nebula is very dependent on your sky conditions. If you have too much light pollution or haze in the air, it can disappear. For this reason, I consider the Flame nebula the "litmus test" for the Horsehead nebula. If the Flame nebula does not "leap out" at you, you need not consider trying to see the Horsehead nebula.

And of course, I'm talking about trained eyes here. A new comer to astronomy may not see the Flame nebula because of their inexperience in looking at such faint objects, even on perfect nights. So for me, I find Alnitak, then nudge the telescope over in the direction of the Flame Nebula. If I can easily see the Flame nebula and its dark lanes, I know it's a good night for hunting the Horsehead nebula. If I have to search for the Flame nebula and use a lot of averted vision to even detect it, I go no further. Averted vision? This is the process of not looking directly at a faint object in order to see it better. Sound silly? Well because of the optic nerve, the center of your eye is not very sensitive, especially in low light situations. A well known astronomer's trick is to look to the side of an object and detect it with their peripheral vision. Another trick is to nudge the telescope slightly. Our eyes can detect moving objects easier. Hitting the trail Believe it or not, the trail from Alnitak to the Horsehead nebula is not very long.

The Horsehead nebula is only about 27 minutes south and slightly east of Alnitak. That's less than the diameter of the full moon. At this point I add my UHC narrow band filter to the optical mix. I start moving the telescope in the southerly direction until I come across the 7.5 magnitude star, SAO132451 (refer to proper chart for your telescope). This star is about 22 minutes from Alnitak. To verify my position and bearings, I then identify two similar magnitude stars nearby. One is SAO 132464, which is a 7.8 magnitude star about 9 minutes to the east and slightly north of SAO 132451. This star has some associated nebulosity and should look a little fuzzy to you. The second star, which is an important one, is SAO 132438, a 7.6 magnitude star that is about 13' southwest of SAO 132451.

I identify SAO 132438 by the fact that there is a tiny 10 magnitude star about 2 minutes to the west of it. I hope all these SAO numbers didn't confuse you. Just take a look at the proper diagram to make sure you know which ones I'm referring to. The main two stars to be concerned with are the first one of SAO 132451, and the last one of SAO 132438. Here's why. If you form a mental image of an equilateral triangle out of these two stars and an imaginary point to the southwest, the Horsehead nebula will be contained within that imaginary corner to the southwest. So, if you have this in your eyepiece, the Horsehead nebula is in your eyepiece! I've been at this point many times and still have not seen the Horsehead nebula. Once I have positively identified this area, I pump up my power a little bit. A little extra power will help to improve contrast on faint objects. I use around 125x to about 180x. I basically try to frame my imaginary triangle as best as I can.

Also, by obtaining a more narrow field of view, you help to exclude the star Alnitak and its glare. Refining the search You should start nudging your telescope slightly and use all the averted imagination, uh I mean averted vision you can muster. If you really concentrate and it really is a good night, you will probably start to pick up the glowing nebulosity that runs from Alnitak to down in this region and contains the dark nebula known as the Horsehead nebula. This is as far as I have gotten. One night with my 10" f/4.5 telescope, I was able to see the band of nebulosity. Another guide might be three tiny, faint stars that "frame" the Horse's head. The stars are about 12.8 magnitude. GSC 4771:1184, GSC 4771:1041, and GSC 4771:1037 seem to curve around the top of the Horse's head. Conclusion Good luck in your search. A frequent comment I've heard is that the Horsehead nebula is bigger than the observer imagined it would be.

Another comment is that it is hard to actually see the shape of the horse's head, but rather you notice a notch in the surrounding glow of nebulosity. The knight chess piece, the horse's head, or even a notch, I'll settle for anything I can get. Hopefully this article will help you and I finally see this beautiful, elusive object known as the Horsehead nebula. Update: Since writing this article, I've actually seen the Horsehead nebula a few times through larger telescopes, ranging from 18" to 24" in size. Charts and Diagrams Figure 1. Full color image of Flame and Horsehead nebula (normal view), courtesy of Anglo-Australian Observatory. Figure 2. Finder chart of Horsehead region. This is a normal view. Figure 3. Finder chart of Horsehead region. This is a mirror view. Figure 4. Negative image of Flame and Horsehead nebula (normal view). Original color image by courtesy of Anglo-Australian Observatory. Figure 5. Negative image of Flame and Horsehead nebula (mirror view). Original color image by courtesy of Anglo-Australian Observatory.

National Optical Astronomy Observatory: Horsehead National Optical Astronomy Observatory About this image About this image This color picture was made by combining several exposures taken on the night of December 28th 1994 (UT of observation 29/12/94 around 04:00) with a 2048x2048 CCD detector at the 0.9m telescope of the Kitt Peak National Observatory. Observing conditions were not ideal throughout, and so only a select few of the original observations were used. The final tally used five frames in the B (blue) filter for a total of 22 minutes, three frames with the V (green) filter, 15 minutes, and two with the R (red), total 10 minutes. Each frame was carefully cleaned, a particularly difficult task for the blue filter due to internal reflection problems in the telescope, and then aligned and combined by computer to create this (approximately) true color picture. The pixel size on the sky is 0.68 arc seconds; after combination, the final size is 1480x1366, or about 17x15 arc minutes.

Orientation of thumbnail image: N to the left, E down. About this object The Horsehead Nebula, a part of the optical nebula IC434 and also known as Barnard 33, was first recorded in 1888 on a photographic plate taken at the Harvard College Observatory. Its coincidental appearance as the profile of a horse's head and neck has led to its becoming one of the most familiar astronomical objects. It is, in fact, an extremely dense cloud projecting in front of the ionized gas that provides the pink glow so nicely revealed in this picture. We know this not only because the underside of the 'neck' is especially dark, but because it actually casts a shadow on the field to its east (below the 'muzzle'). The marked change in the density of stars visible on either side indicates that the strip of glowing hydrogen marks the edge of a substantial dark cloud. As a cloud core emerging from its parental cloud, and as an active site of low-mass star formation, the Horsehead is a simple system of considerable use for testing models of photodissociation regions, and revealing the intricate interrelations between gas, dust, and the light from hot stars.

Polarization maps suggest that the entire region is illuminated by the bright OB star Sigma Orionis, which is also responsible for exciting the emission nebula. (The much brighter Zeta Orionis is a foreground star, not related to the nebulosity.) The 'streamers' visible in the brighter region appear to be due to a magnetic field which leaves the Horsehead cloud approximately radially, having been entrained by outflowing matter. Small red spots in the base of the Horsehead betray the presence of hidden protostars, and red streaks near the yellowish nebula surrounding V615 Orionis (bottom left) are Herbig-Haro objects, which are jets of material ejected from protostars. The Horsehead is a fascinating, active, and complex neighborhood. Location: 05 38 27 -02 29 (1950.0), constellation of Orion. Distance: about 1600 light-years. Facts About the Dark Horsehead Nebula in the Constellation Orion Some Basics Barnard 33 is in the constellation Orion , which is best seen in the northern hemisphere during the winter.

The nebula is about 1,550 light years from here, and it’s dimensions are about 2.7 x 18 light years. It’s rather far out at the edge of the galaxy with respect to the Sun, but can be seen with a 10 inch telescope with a hydrogen beta filter. What many people who see pictures of the Nebula don't realize is that it’s not pointing north, but pointing west. In other words, if you were on the Enterprise and approaching this huge area of space, its famous horse’s head shape would be lying on its side. And it probably wouldn’t look too much like a horsehead. Rotate it 90°, and the horse's head appears! slide 2 of 5 Discovery Barnard 33 was discovered by the astronomer Williamina Fleming. She was not only a woman astronomer, which was rare in 1881, but came to the profession by accident. Fleming was born in Scotland and moved with her husband to the United States as a young woman. When her husband left her while she was pregnant, she was hired as the maid of Harvard professor Edward Charles Pickering, who was also the director of the college’s observatory.

Later, he hired Fleming as a sort of secretary at the observatory. She was ultimately hired to catalogue stars when Pickering grew disgusted with his slacking male assistants and claimed Fleming, a mere housekeeper, could do better than they could. He was right. Fleming invented a system where she catalogued stars depending on the hydrogen in their spectra. The spectrum is a band of color into which the light of a star can be separated. They’re the colors of the rainbow: red, orange, yellow, green, blue, indigo and violet. The mnemonic used to remember this spectrum is name, ROY G BIV. Molecules, atoms and ions radiate most strongly at certain colors. Fleming found more than 10,000 stars, as well as other deep space objects. These stars were later grouped into the Henry Draper Catalogue. Of course, for a long time Fleming’s boss, Mr. Pickering, got the credit for her work. She discovered Barnard 33, or the Horsehead Nebula in 1888, on plate B2312.

slide 3 of 5 Dark Nebula The nebula is a dark, or absorption nebula, which means that it’s a cloud that is so dense that it blocks out or absorbs the light of the glowing emission nebula behind it, in this case IC 434. Nebulae, from the Greek word for “cloud," are made of gas and tiny dust particles enclosed in shells of nitrogen and carbon monoxide ice. The temperature of a nebulae is about 10 degrees K. This temperature is so cold that scientists speculate that the nebula will eventually collapse in on itself, and the pressures generated will begin the ignition of proto-stars. Both IC 434 and Barnard 33 are part of the Orion Molecular Cloud and join a group of beautiful nebulae in the belt of Orion. Molecular Clouds are clouds found in outer space that are dense enough to allow molecules to form. Some of the molecules are water, ammonia, formaldehyde, acetylene, methyl alcohol, methyl cyanide, vinyl cyanide, formic acid and others.

A molecular cloud can be from 104 to 106 times the mass of the Sun and they often shroud developing stars, like the shells of eggs around embryos. Other nebulae in the molecular cloud besides the Barnard 33 are the Orion Nebula, Barnard’s Loop, M78 and the Flame Nebula. Barnard 33 is visually near the star Alnitak, though in reality the star is about 700 to 800 light years closer than the nebula. Alnitak is really three stars in the easternmost part of Orion’s Belt. The primary is a very hot O class supergiant whose diameter is at least 20 times larger than the Sun’s. slide 4 of 5 IC 434 IC 434, the emission nebula the Horsehead Nebula sits in front of, is pinkish red and glows because of ionized hydrogen gas. A hydrogen molecule is ionized when it’s so hot that electrons are added or removed from it. The nebula is pinkish because hydrogen glows with the most intensity at the red end of the spectrum.

Because a nebula like IC 434 is made mostly of ionized hydrogen, it’s called an H II region. These regions are commonly the cradles of some extremely hot O and B stars. This would be called an O-B association. In the case if IC 434, the hydrogen is being heated by the multiple star system Sigma Orionis, whose primary stars are a Sigma Orionis AB, a young O-B association. Together, they’re about 32,500 times as luminous as the Sun. slide 5 of 5 Horsehead Nebula | astronomy | Britannica.com Horsehead Nebula Trifid Nebula Horsehead Nebula, (catalog number IC 434), ionized-hydrogen region in the constellation Orion . The nebula consists of a cloud of ionized gas lit from within by young, hot stars; a dark cloud containing interstellar dust lies immediately in front. The dust absorbs the light from part of the ionized cloud. A portion of this dark cloud has a shape somewhat resembling a horse’s head. The nebula is located 400 parsecs (1,300 light-years) from the Sun.

It has a diameter of approximately 4 parsecs (13 light-years) and a total mass of about 250 solar masses. Horsehead Nebula Corrections? Updates? Help us improve this article! Contact our editors with your feedback. MEDIA FOR: You have successfully emailed this. Error when sending the email. Try again later. Edit Mode Submit Tips For Editing We welcome suggested improvements to any of our articles. You can make it easier for us to review and, hopefully, publish your contribution by keeping a few points in mind. Encyclopædia Britannica articles are written in a neutral objective tone for a general audience. You may find it helpful to search within the site to see how similar or related subjects are covered. Any text you add should be original, not copied from other sources. At the bottom of the article, feel free to list any sources that support your changes, so that we can fully understand their context. (Internet URLs are the best.) Your contribution may be further edited by our staff, and its publication is subject to our final approval. Unfortunately, our editorial approach may not be able to accommodate all contributions. Submit Thank You for Your Contribution!

Our editors will review what you've submitted, and if it meets our criteria, we'll add it to the article. Please note that our editors may make some formatting changes or correct spelling or grammatical errors, and may also contact you if any clarifications are needed. Uh Oh There was a problem with your submission. Please try again later. Close Date Published: September 18, 2008 URL: Access Date: January 18, 2017 Share Space Images | Horsehead Nebula Images | December 1, 1999 Horsehead Nebula Rising from a sea of dust and gas like a giant seahorse, the Horsehead nebula is one of the most photographed objects in the sky. NASA's Hubble Space Telescope took a close-up look at this heavenly icon, revealing the cloud's intricate structure. This detailed view of the horse's head is being released to celebrate the orbiting observatory's eleventh anniversary. Produced by the Hubble Heritage Project, this picture is a testament to the Horsehead's popularity. Internet voters selected this object for the orbiting telescope to view. The image can be view at .

The Horsehead, also known as Barnard 33, is a cold, dark cloud of gas and dust, silhouetted against the bright nebula, IC 434. The bright area at the top left edge is a young star still embedded in its nursery of gas and dust. But radiation from this hot star is eroding the stellar nursery. The top of the nebula also is being sculpted by radiation from a massive star located out of Hubble's field of view. Only by chance does the nebula roughly resemble the head of a horse. Its unusual shape was first discovered on a photographic plate in the late 1800s. Located in the constellation Orion, the Horsehead is a cousin of the famous pillars of dust and gas known as the Eagle nebula. Both tower-like nebulas are cocoons of young stars. The Horsehead nebula lies just south of the bright star Zeta Orionis, which is easily visible to the unaided eye as the left-hand star in the line of three that form Orion's Belt. Amateur astronomers often use the Horsehead as a test of their observing skills; it is known as one of the more difficult objects to see visually in an amateur-sized telescope.

The magnificent extent of the Horsehead is best appreciated in a new wide-field image of the nebula being released today by the National Optical Astronomy Observatory, taken by Travis Rector with the National Science Foundation's 0.9 meter telescope at Kitt Peak National Observatory near Tucson, AZ. This popular celestial target was the clear winner among more than 5,000 Internet voters, who were asked last year to select an astronomical target for the Hubble telescope to observe. The voters included students, teachers, and professional and amateur astronomers. This 11th anniversary release image was composed by the Hubble Heritage Team, which superimposed Hubble data onto ground-based data (limited to small triangular regions around the outer edge of the image). Ground-based image courtesy of Nigel A. Sharp (NOAO/AURA/NSF) taken at the 0.9-meter telescope on Kitt Peak. Image credit: JPL/NASA, NOAO, ESA and The Hubble Heritage Team, (STScI/AURA) Wallpaper Rating is available when the video has been rented. This feature is not available right now. Please try again later.

Published on Nov 4, 2014 The Horsehead Nebula (also known as Barnard 33 or IC 434) is a dark nebula in the constellation Orion. The Horsehead Nebula is approximately 1500 light years from Earth. It is one of the most identifiable nebulae because of the shape of its swirling cloud of dark dust and gases, which bears some resemblance to a horse's head when viewed from Earth. The dark cloud of dust and gas is a region in the Orion Molecular Cloud Complex where star formation is taking place. This stellar nursery, as it is known, can contain over 100 known organic and inorganic gases as well as dust consisting of large and complex organic molecules. credit: ESA - Hubble Visualizations Horsehead Nebula | StarDate Online Horsehead Nebula 3D Horsehead A dark cloud of dust forms the outline of a horse's head in this image shot through a telescope at McDonald Observatory. The outline, known as the Horsehead Nebula, is silhouetted against a more-distant cloud of glowing hydrogen gas, which is energized by hot young stars. The energy from those stars is slowly eroding the Horsehead.

[Tom Montemayor/McDonald Observatory] If you watch the clouds on a lazy afternoon, you’ll see all kinds of shapes drift by — dragons, castles, presidents, and more. The same thing happens as you watch the clouds of gas and dust that fill the Milky Way galaxy — watch long enough, and familiar shapes will pop into view. One looks like California, another resembles North America, and still another looks like an eagle. Like the clouds in an afternoon sky, though, the celestial clouds will evaporate and disappear from view. Consider one of the most famous objects in the sky, the Horsehead Nebula in the constellation Orion. It’s actually formed by two clouds. One is a bright pink cloud of hydrogen gas. It’s zapped by ultraviolet radiation from hot young stars, so it glows like a neon bulb. The second cloud is in front of this one, and it consists of cool, dark gas. It blocks the light of the bright cloud behind it, forming the outline of a horse’s head. But the Horsehead is slowly vanishing. The same stars that cause the pink cloud to glow are eroding the dark cloud that forms the nebula. Within a few thousand years, it’ll disappear entirely.

For now, look for the Horsehead beginning in mid-evening. It stands just below Orion’s Belt, a short line of three bright stars that stands almost straight up from the southeastern horizon by about 8 o'clock. The Horsehead is small and faint, but if you have dark skies, it’s visible in fairly small telescopes. Script by Damond Benningfield, Copyright 2011 Horsehead Nebula Region Horsehead Nebula Region The bright star Alnitak (Zeta Orionis, the easternmost star in Orion's belt) is at the center of one of the most remarkable and picturesque regions in the sky. The radiation of this hot star excites the gas in the surrounding nebulae and causes it to emit light. The nebula strip running south from Alnitak is the designated IC 434, into which the famous dark nebula called the Horsehead Nebula (Barnard 33) protrudes from the eastern side. The dark nebula's shape resembles the head and neck of a horse, hence its name. Dark nebulae are clouds of dust in space that obscure stars and other objects behind them.

The other nebula on to the east of Alnitak is called the Flame Nebula (NGC 2024). It is overlayed by several dark lanes, the main one of these splits NGC 2024 into two parts. This nebula certainly has a flame-like appearance. Its western part is also overlayed by blue glare from the star Alnitak. The unusual color of this nebula has been noticed, in color photographs it usually appears yellow or a sort of orange almost unique to this object. To the upper left of the Horsehead is the blue reflection nebula NGC 2023. Other reflection nebulae in this photo are IC 431, IC 432 and IC 435, all of them located around bright stars. Along with the Great Orion Nebula M42/43 and its surrounding nebulae, this region is part of a large nebulous complex where stars are forming out of the dust and gas. Located at a distance of about 1,500 light years, this complex is the closest star forming region to our own solar system.

Exposure: 8 x 10 min + 2 min Camera: Modified Nikon D70 Digital SLR Sensitivity: ISO 1600 Location: Turmkogel near Puchenstuben, Lower Austria Conditions: Visual limiting magnitude 6.2-6.3 mag, Seeing 3, Temperature -1.5°C, no wind, low humidity Autoguider: Meade Pictor 216 XT, max. error: 2 Enhancement: Adobe Photoshop CS 8.0, SGBNR 1.0.4 Observing Hints The Horsehead Nebula in Orion is a well-known photo target, pictures of it are found in many astronomy textbooks and surely every astrophotographer is proud to present his own version of the famous dark nebula. Indeed these photos look spectacular: The orange-red Flame Nebula NGC 2024, the deeply red nebulous stripe IC 434 with the high-contrast dark protrusion of the Horsehead Nebula B33 and the brilliant blue-white star Alnitak (Zeta Ori) make for a nice composure.

Visual observers, drawn by these colorful impressions, are of course tempted to try their luck with B33. Often they get disappointed because the Horsehead is a tough challenge for not-so experienced skywatchers. Seeing the Horsehead is possible in a premium 6-inch telescope, but it takes a perfectly dark sky and much skill in using averted vision. A Hβ filter is very helpful. But first, B33 must be located. That is not a difficult task, as the three belt stars of Orion are conspicuous to the naked eye, Alnitak is the easternmost of them. Immediately to the east of Alnitak the Flame Nebula NGC 2024 is located, which is quite bright and would be easily observable but for the extremely bright star Alnitak, which outshines the Flame Nebula and tends to ruin an observer's dark adaption. Positioning Alnitak outside the field stop should help. As the flame nebula is not small, using low magnification makes sense. At least the dark central lane which bisects the nebula should be readily observable, even without filter; if not, forget about observing the Horsehead - the Flame Nebula is a good indicator for that.

The next step is finding IC 434, which is a stripe of nebulosity running in north-southern direction. It is a lengthy stripe, therefore low magnification is again adequate, an exit pupil of 4.5 to 5 millimeters should be ok. More is usually not practical because the sky is seldom that dark... A Hβ filter is extremely helpful for detecting IC 434 because the nebula's contrast against the sky background increases a lot. The observability of IC 434 is another indicator for detecting the Horsehead: If it just very faint in the Hβ filter, B33 will be hard if not impossible. Ok, now for the real challenge: Hunting for B33. First, take a look at a detailed sky chart or check a photograph for the position of the dark nebula in correlation to the surrounding stars. Starting at Alnitak and going south, there are two relatively bright stars, the first one fainter, the second one brighter, of 7th magnitude. These two mark the higher-contrast eastern edge of IC 434.

East of the second star there is another star surrounded by not-so-faint nebulosity designated NGC 2023. Drawing an imaginary line from NGCC 2023 to the 7th magnitude star, and extending it across IC 434, you will find another two relatively bright stars (the northern one brighter, the southern one fainter) not quite aligned with the eastern edge of IC 434. Exactly there, at the eastern edge of IC 434, B33 is located. To see it, use averted vision and keep the eye steady by fixing one of the stars. If the conditions are excellent and you get a little experience in observing B33, you can even detect the Horsehead shape so well-known from photographs: The neck, the straight edge above the head, and a little bit of the snout, which dissolves into the nebulous background. If the sky is extremely dark, it is possible for a skilled observer to detect B33 without Hβ filter, but more than a break in the nebulous band IC 434 can usually not be seen.

The fact that seeing the Horsehead in a 6" scope is actually not extremely difficult for an experienced observer makes detection reports with smaller apertures under perfectly dark skies plausible. There are reports (by Jay Reynolds Freeman) about a detection of B33 in his youth with a 4.5" Newtonian, without any filter. But that takes an extremely dark sky and his excellent eyes. Hunting for B33 is easier in an 8" telescope, where seeing the Horsehead in an Hβ filter is not extremely tough for an experiences observer, there are other more difficult challenges than that. Using 10 inches of aperture, an UHC filter is adequate and the task is not very difficult. Taking a big step upwards, in an 18-inch telescope and with H-Beta filter the full figure of the Horsehead is readily observable, including the snout. Disregarding the telescope, the observability of the Horsehead Nebula is strongly dependant on sky conditions; and if you have once detected it, doing so again is not any longer that difficult.

Question: In which constellation would you find the Horse Head nebula?
Answer: Orion